The investigators are currently following a regional cohort of 58 children with less that 750 g birth weight from early school age through a mean age of 14 years, together with matched comparison groups of 53 children with 750-1499 g birth weight and 62 term-born controls. Their findings show higher rates of both global and specific developmental disorders in less that 750 g children, with evidence for continuing and even increasing sequelae over time. The purposes of the continuation project are to extend follow-up of this sample into middle to late adolescence (mean age 16 years), examine brain status via magnetic resonance imaging (MRI), and investigate the validity of biological and social-familial risks in accounting for variability in outcome. In addition to tracking outcomes measured previously, the investigators will administer neuropsychological tests sensitive to the types of brain insults sustained by low birth weight children. MRIs will be obtained concurrently, and outcomes examined in relation to morphometric measures of specific brain structures. Hypothesis 1 is that sequelae of less than 750 g birth weight will become more pronounced in mid to later adolescence. Consistent with a gradient of low birth weight effects, the investigators anticipate sequelae in both low birth weight groups relative to term-born controls, with more marked effects in the less that 750 g group. Hypothesis 2 is that MRI-based morphometry will identify abnormalities in brain structure in both low birth weight groups relative to term-born controls, with more severe abnormalities in the less than 750 g group. Hypothesis 3 is that biological and social-familial risks will account for individual differences in adolescent outcomes and in changes observed over the school-age years. Specific structure-function relationships are anticipated in relating brain morphology to measures of memory, executive function, and visual-perceptual skill. Results will clarify the long-term sequelae of less than 750 g birth weight and shed light on the bases of both adverse consequences and developmental sparing.